NEXSENS T-Node FR Thermistor String User Guide
- June 10, 2024
- NEXSENS
Table of Contents
NEXSENS T-Node FR Thermistor String
QUICK START GUIDE
Wiring Connection Table 1
| Receptacle Pin | Wire Color |
|---|---|
| 1 | Green |
| 2 | Blue |
| 3 | Brown |
| 4 | Red |
| 5 | White |
| 6 | Yellow |
| 7 | Black |
| 8 | Orange |
Figure 1: NexSens T-Node FR Thermistor String.
Overview
The T-Node FR Thermistor String is a temperature sensor string that can be
used for temperature monitoring in water bodies. The sensor string is made up
of multiple temperature nodes that can be connected together to form a string.
The temperature readings can be obtained through a Modbus controller or a
NexSens X2-Series data logger.
Sensor Information: The sensor string has a receptacle pin that can be
connected to a UW-FLxR cable to obtain temperature readings. The wiring
connection table provides details on how to connect the receptacle pin to the
UW-FLxR cable. The sensor string has a pass-through for RS485-A, RS485-B,
12VDC, and GND. The Modbus-RTU Register Information Table 2 provides details
on how to read the temperature using the Modbus controller. The Universal
Modbus Address can be used to read the current node address.
Specs: The T-Node FR Thermistor String is programmed to respond to Modbus
address 251. The temperature readings are provided in 32-bit Float Big-endian
format. The sensor string can be connected to a NexSens X2-Series data logger
for autodetection and temperature readings.
Figure 2: UW-FLxR receptacle cable pinout.
Note: The UW-Receptacle to flying lead cable is a separate accessory that
may be purchased for integration with a third-party Modbus controller. It is
not needed to connect the temperature string to a NexSens X2-Series data
logger.
NexSens Data Logger Connection:
- Setup your data logger on WQData LIVE by following the included data logger quick start guide with your order.
- Plug the string into an open sensor port on the data logger for autodetection.
- After the next logger reading:
- Confirm that all temperature nodes on the string have been recognized.
- Ensure that each show valid temperature readings.
- Gather a few readings before deployment.
IMPORTANT – BEFORE FIELD DEPLOYMENT:
Ensure to connect a UW plug on the last node of the string to prevent water
intrusion.
Usage Instructions:
- Connect the T-Node FR Thermistor String receptacle pin to the UW-FLxR cable based on the wiring connection table.
- If using a Modbus controller, refer to the Modbus-RTU Register Information Table 2 to read the temperature.
- If using a NexSens X2-Series data logger, plug the string into an open sensor port for autodetection and temperature readings.
- Ensure that all temperature nodes on the string have been recognized and are showing valid temperature readings before deployment.
- Connect a UW-plug on the last node of the string to prevent water intrusion before field deployment.
For additional information, refer to the T-Node FR Resource Library on the NexSens Knowledge Base or contact NexSens at 937-426-2703 or visit their website at www.nexsens.com.
QUICK START GUIDE
Figure 1: NexSens T-Node FR Thermistor String.
Overview
The NexSens T-Node FR Thermistor String features a series of connected sensors containing integral titanium thermistors secured in protective housings. Each sensor is accurate to +/- 0.075°C. Readings stabilize within 60 seconds due to the thermistor’s direct contact with water. Temperature data is transmitted on an RS-485 Modbus RTU string bus for integration with data loggers and SCADA systems. The string is powered by 4-28 VDC for operation on a 12 or 24 VDC power supply. Strings terminate in a NexSens UW plug and receptacle connector, allowing additional sections or sensors to be added.
Sensor Information
Specs
- Dimensions: 13.46 cm L x 3.56cm Dia. (5.3 “L x 1.4” Dia.)
- Range: 0 to 45°C (32 to 113°F)
- Resolution: 0.01°C
- T90 Response Time: 60 seconds
- Maximum Depth: 200m (656 ft.)
- Maximum Length: 1219m (4000 ft.)
General
- Power: 5-24 VDC
- Protocol: RS-485 (Modbus-RTU)
- Baud Rate: 19200
- Parity: N81
- Default Starting Address: 1*
- Format: Big Endian
- Timeout: 500 ms
On a T-Node FR string with multiple nodes, the nodes should be addressed in increasing numerical order.
Wiring Connection
Table 1: Wiring Table for UW-FLxR Cable.
Receptacle Pin
|
Wire Color
|
T-Node FR Signal
---|---|---
1| Green| RS485-A
2| Blue| RS485-B
3| Brown| Pass-Through
4| Red| 12VDC
5| White| —
6| Yellow| Pass-Through
7| Black| GND
8| Orange| Pass-Through
Figure 2: UW-FLxR receptacle cable pinout.
Note: The UW-Receptacle to flying lead cable is a separate accessory that
may be purchased for integration with a third-party Modbus controller. It is
not needed to connect the temperature string to a NexSens X2-Series data
logger.
Modbus-RTU Register Information
Table 2: Read temperature.
Function 0x04 (Read Input Registers)
Registers
|
Data Type
|
Data Size
|
Purpose
0x0006,0x0007
|
32-bit Float Big-endian
|
2 Registers
| Requests the temperature recorded in °C.
Example Input: 01,04,00,06,00,02,91, CA
- Requests the temperature reading from address 1.
Example Output: 01,04,04,41,AF,38,1D,0C,50
- The sensor responds with 0x41af381d (21.9024°C).
Table 3: Change Modbus address.
Function 0x10 (Write Multiple Registers)
Registers
|
Data Type
|
Data Size
|
Purpose
0x1000
|
16-bit integer
|
1 Register
| Changes the Modbus address of the first node on the TS210 string*.
Assuming the first node of the string begins with address 1
Example Input: 01,10,10,00,00,01,02,00,05,77,92
- Changes Modbus address from 1 to 5.
Example Output: 01,10,10,00,00,01,05,09
- The sensor responds acknowledging the new address.
Universal Modbus Address
The T-Node FR is programmed such that any sensor will respond to Modbus
address 251. This is implemented in the event that the sensor’s current
address is unknown.
Note: This address should only be queried with one sensor connected to
the data line. If more than one sensor is connected, both will respond and a
bad message is likely.
Table 4: Read the current address using the universal address.
Function 0x04 (Read Input Registers)
Registers
|
Data Type
|
Data Size
|
Purpose
0x1000
|
16-bit integer
|
1 Register
| Uses the universal address
(251) to read the current node address.
Example Input: FB,04,10,00,00,01,21,50
- Uses universal address (FB) to read current address.
Example Output: FB,04,02,00,07,20, E6
- The current Modbus address is 7 (0x0007).
NexSens Data Logger Connection
Setup your data logger on WQData LIVE by:
- Following the included data logger quick start guide with your order.
- Visiting the NexSens Knowledge Base nexsens.com/knowledge-base-v2.
Plug the string into an open sensor port on the data logger for autodetection.
After the next logger reading:
- Confirm that all temperature nodes on the string have been recognized.
- Ensure that each shows valid temperature readings.
- Gather a few readings before deployment.
IMPORTANT – BEFORE FIELD DEPLOYMENT: Ensure to connect a UW plug on
the last node of the string to prevent water intrusion.
For additional information, please reference the T-Node FR Resource Library on
the NexSens Knowledge Base. nexsens.com/tnodekb.
- 937-426-2703
- www.nexsens.com.
- 2091 Exchange Court
- Fairborn, Ohio 45324
References
- Knowledge Base - NexSens
- Knowledge Base - NexSens
- NexSens Technology Inc. - Better Data. It's what we do
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